Diaphragm cell for high-temperature diffusion measurements. Tracer Diffusion coefficients for water to 363 K

1989 ◽  
Vol 85 (5) ◽  
pp. 1091 ◽  
Author(s):  
Allan J. Easteal ◽  
William E. Price ◽  
Lawrence A. Woolf
Keyword(s):  
High Temperature ◽  
Diffusion Coefficients ◽  
Tracer Diffusion ◽  
Temperature Diffusion ◽  
Diaphragm Cell ◽  
Tracer Diffusion Coefficients

High-temperature diffusion of oxygen in synthetic diopside measured by nuclear reaction analysis

1999 ◽  
Vol 63 (5) ◽  
pp. 673-686 ◽  
Author(s):  
L. Pacaud ◽  
J. Ingrin ◽  
O. Jaoul
Keyword(s):  
High Temperature ◽  
Nuclear Reaction ◽  
Diffusion Coefficients ◽  
Tracer Diffusion ◽  
Nuclear Reaction Analysis ◽  
Gas Mixture ◽  
Diffusion Study ◽  
Self Diffusion ◽  
Temperature Diffusion ◽  
Diffusion Profiles

AbstractWe have performed O self-diffusion experiments in synthetic diopside single crystals along the b-axis at temperatures ranging from 1473–1643 K, under controlled O partial pressure (10−11–10−2 atm). The 18O tracer diffusion was imposed by solid/gas exchange between 16O in diopside and 18O2-enriched argon-hydrogen-H2O gas mixture. Diffusion profiles of 18O were measured by Nuclear Reaction Analysis 18O (p,α) 15N. The diffusion coefficients are described by , with log D0(m2/s)=−9.2 ± 1.0 and E 310 ± 30 kJ/mol.Our results are in agreement with Ryerson and McKeegan's (1994) data and Farver's (1989) data along a direction perpendicular to the c direction. Experiments performed in a wide pO2 range show that D is independent of pO2.We observe no change in the diffusion regime up to 1643 K (i.e. 22 K prior to melting temperature). This result differs from the diffusion study of Ca in diopside by Dimanov and Ingrin (1995), where a strong enhancement of Ca mobility, attributed to an excess disorder in the Ca-sublattice, was observed above 1523 K. We conclude that O diffusion in diopside is not affected by this premelting phenomenon.

Tracer diffusion coefficients of tritiated water and acetonitrile in water + acetonitrile mixtures

1980 ◽  
Vol 33 (8) ◽  
pp. 1667 ◽  
Author(s):  
AJ Easteal
Keyword(s):  
Diffusion Coefficients ◽  
Structural Model ◽  
Tritiated Water ◽  
Tracer Diffusion ◽  
Solution Viscosity ◽  
Composition Region ◽  
Self Diffusion ◽  
Composition Variation ◽  
Diaphragm Cell ◽  
Tracer Diffusion Coefficients

Tracer diffusion coefficients of tritiated water (HTO) and 14C-labelled acetonitrile have been measured at 298.15 K by the diaphragm cell method, for the whole range of compositions of water+ acetonitrile binary mixtures. The composition variation of (a) the deviation of D from additivity and (b) the product Dη, for each component, has been evaluated. The variation of Dη is discussed in terms of the Naberukhin- Rogov structural model for solutions of non-electrolytes in water. ��� The diffusion data have been used to test a semiempirical relationship, between solution viscosity and self-diffusion coefficients, due to Albright. For the composition region of 5-55 mole % acetonitrile Albright's equation gives calculated viscosities which agree well with observed values. The calculation fails to reproduce the observed variation of viscosity for the composition region of 60-95 mole % acetonitrile.

Tracer diffusion in aqueous sucrose and urea solutions

1990 ◽  
Vol 68 (9) ◽  
pp. 1611-1615 ◽  
Author(s):  
Allan J. Easteal
Keyword(s):  
Diffusion Coefficients ◽  
Relative Viscosity ◽  
Tracer Diffusion ◽  
Proton Exchange ◽  
Specific Viscosity ◽  
Sucrose Solutions ◽  
Diaphragm Cell ◽  
Tracer Diffusion Coefficients ◽  
Viscosity Dependence

Tracer diffusion coefficients for water (as HTO), methanol (14CH3OH), and acetonitrile (CT3CN) in aqueous sucrose (10–25% w/w) and urea (0.25–4 mol L−1) solutions at 298 K have been determined using the diaphragm cell technique. For sucrose solutions tracer diffusion coefficients vary with the 2/3 power of the relative viscosity and the viscosity dependence is the same for the above tracers as for sucrose and oxygen. In urea solutions tracer diffusion coefficients appear to have a solute-specific viscosity dependence, but the solute specificity is largely removed when the effects of proton exchange and urea dimerisation are considered. Keywords: diffusion, water, methanol, acetonitrile, sucrose, urea.

Tracer Diffusion of Fe and Pd in FePt and FePt3

2005 ◽  
Vol 237-240 ◽  
pp. 450-455 ◽  
Author(s):  
Y. Nosé ◽  
Teruyuki Ikeda ◽  
Hideo Nakajima ◽  
Hiroshi Numakura
Keyword(s):  
High Temperature ◽  
Diffusion Coefficients ◽  
Transformation Temperature ◽  
Tracer Diffusion ◽  
Arrhenius Plots ◽  
Tetragonal Axis ◽  
Tracer Diffusion Coefficients ◽  
Ordered State

The tracer diffusion coefficients of Fe and Pd have been measured in FePt and FePt3 by standard radiotracer experiments. In FePt3 the diffusion coefficients are lower than extrapolations of those in the high-temperature disordered state, exhibiting curved Arrhenius plots below the transformation temperature. The diffusion of Pd is faster than that of Fe, and noticeable dependence on composition is found for the latter. In the L10 ordered FePt, the diffusion of Fe has been verified to be slower in the direction of the tetragonal axis, but the case of Pd appears more complex. The diffusion coefficients of Fe and Pd are similar in magnitude in the L10 ordered state.

Non-Stoichiometry and Cation Tracer Diffusion Studies in the Magnetite-UlvÖSpinel Solution, (Fe,Ti)3-δO4

1994 ◽  
Vol 369 ◽  
Author(s):  
Sanjeev Aggarwal ◽  
Rudiger Dieckmann
Keyword(s):  
Diffusion Coefficients ◽  
Tracer Diffusion ◽  
Oxygen Activity ◽  
Spinel Solid Solution ◽  
Low Oxygen ◽  
Cation Diffusion ◽  
Deviation From Stoichiometry ◽  
Diffusion Studies ◽  
Tracer Diffusion Coefficients ◽  
Point Defect Structure

AbstractCation diffusion in the spinel solid solution (Fe1-xTix)3-δO4 (0≤ x ≤ 0.3) was investigated at 1200 ºC as a function of oxygen activity, aO2 and cationic composition, x. At different cationic compositions, cation tracer diffusion coefficients, D*Me of Me = Fe and Ti were measured as a function of oxygen activity. Plots of log DMe vs. loga0 show V-shaped curves, indicating that different types of point defects prevail at high anc low oxygen activities. Thermogravimetric experiments were conducted, using a high resolution microbalance, to determine the deviation from stoichiometry in (Fe1-xTix)3-δO4 at 1200 °C. δversus log aO2 curves are S-shaped. An analysis of the oxygen activity dependences of thecation diffusion coefficients and the deviation from stoichiometry with regardto the point defect structure suggests that at high oxygen activities cation vacancies are the predominant defects governing the deviation from stoichiometry and the diffusion ofcations. At low oxygen activities, and at small values of x, cation interstitials determine the deviation from stoichiometry, while they dominate for 0 ≤ x ≤ 0.3 inthe cation diffusion.

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